.* Regex Tester & Debugger

Test a JavaScript regular expression against your text — live match highlighting, capture groups, and flag toggles. Everything runs in your browser.

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About this tool

Write a JavaScript regular expression and see every match highlighted in your sample text as you type. The Regex Tester lists capture groups for each match, supports all JavaScript flags (g, i, m, s, u, y), and tells you immediately when a pattern is invalid — no more guessing why your regex matched nothing.

Because it uses the browser's own regex engine, what you see here is exactly what your JavaScript or TypeScript code will do. Test data stays in your browser.

How to use it

  1. Type or paste the pattern and choose flags.
  2. Paste sample text — matches highlight live.
  3. Expand a match to see its numbered and named capture groups.
  4. Copy the working pattern into your code.

Frequently asked questions

Which regex flavour is this?

JavaScript (ECMAScript), the engine built into your browser. Most patterns also work in other languages, but look-behind, named groups and Unicode property escapes differ between engines.

Does it support named groups?

Yes — use (?<name>...) and the group list will show the names.

Is my test text uploaded?

No. Everything runs in the browser.

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